Former Iranian hostage C. Cortlandt Barnes of Leland, N.C., poses with his dog Ginger from his home in, November, 2013. Barnes disagrees with the current nuclear treaty deal with Iran. In 1979 he was one of 52 Americans who were held for 444 days by the Iranians during the Carter Administration.

Washington — The United States has a veto in the United Nations Security Council by virtue of being one of the council’s five permanent members granted that power by the institution’s charter. But should the US be able to veto a country’s selection of its ambassador to the UN in New York simply because UN headquarters is located on American soil?

Traditionally the US has recognized that it has no right to intervene in a country’s choice of a UN ambassador – but that stance is being tested with the news that Iran intends to send a diplomat who was involved in the 1979 hostage-taking at the American Embassy in Tehran as its representative in New York.

Incensed members of Congress from both sides of the aisle are calling on the Obama administration to deny the Iranian, Hamid Abutalebi, both a visa to enter the US and the diplomatic immunity to which an ambassador would be entitled.

A “slap in the face” of the United States, Sen. Charles Schumer (D) of New York and Sen. Lindsey Graham (R) of South Carolina both said in decrying Iran’s intention. “Willfully, deliberately insulting and contemptuous,” said Sen. Ted Cruz (R) of Texas.

“We shouldn’t accept him,” said Sen. John McCain (R) of Arizona. “We should change our rules or laws if we have to so that somebody who is guilty of that kind of behavior should not be allowed in the United States of America.”

Senator Cruz is proposing legislation that would bar a known terrorist from entering the US as a UN ambassador – although it was not clear how such a law would affect Mr. Abutalebi.

At the State Department, officials say that as “troubling” as Iran’s plans may be, the US is generally obligated to admit the chosen representatives of the UN’s 193 member countries. “We do take our obligations as host nation for the United Nations very seriously,” says Marie Harf, State Department deputy spokeswoman.

Abutalebi, the choice of Iranian President Hassan Rouhani for the New York post, has a reputation these days as a moderate, according to some Iran diplomatic experts. But in 1979 he was a member of the Muslim Student Followers of the Imam’s Line, the group that occupied the US Embassy and instigated the hostage-taking in which embassy workers were held for 444 days.

Abutalebi did not hold a leadership position in the group, according to reports about his student days and later career, but members of Congress and some of the former hostages say his involvement in the crisis is enough to disqualify him.

But some UN experts say the fact remains that the US has no right to “pick and choose” other countries’ UN ambassador – and that it’s not up to the US to give a thumbs up or down based on a diplomat’s past.

“Good heavens,” says Michael Doyle, a former UN official and now an expert in international and public affairs at Columbia University in New York. “It’s like discovering someone was in the SDS in the 1960’s.”

One could question President Rouhani’s choice given the image the Iranian leader has tried to convey and the ties he has seemed to want to rebuild with the US, Mr. Doyle says, but that doesn’t change US obligations concerning the UN, he adds.

“It may not have been the wisest choice for Iran to make given Rouhani’s efforts to make nice,” he says, “but it’s their choice.”